Magic question, what lenses will you have with that camera? Body only, yes, the d40 will potentially blow away your P&S, but you will need some useful lenses for it.

Don't let the MP count fool you. A good 6mp shot can look better printed out at larger sizes than most any 10mp point and shoots... But a bad photo is still a bad photo, no matter what camera you use... ;)

Just be prepared to spend some money on lenses... That's all.. ;)